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MASTER NOTES: Above Average

As you might have heard, tons of new tools are arriving in baseball. Stadiums have so many radars, lasers, sonars and cameras that they’re like CIA installations, plus expensive hot dogs. And ridiculously expensive beer.

One of the interesting challenges in all of this, besides finding a mortgage lender to help you afford a hot dog and a beer, is how to apply all the data pouring in from the various measurement systems.

One of the really hot topics these days is Exit Velocity, the speed at which a batted ball leaves the bat. We see references to “EV” everywhere nowadays, even the notoriously slow-adapters who run baseball broadcasts. (The fact that the booth ninnies have enthusiastically embraced EV makes you suspicious that the stat is of any use.)

But in this rare case, their endorsement doesn’t automatically mean the whole thing is a bad idea—even the math-averse, analysis-averse booth ninnies can get their heads around the speed of the batted ball, as they previously did with the thrown ball. In fact, pitch velocity has become something of a crutch for baseball announcers, but that’s a rant for another day.

In the more analytically inclined fantasy community, EV has also become quickly established as a go-to metric. But here’s the thing: I wonder if it’s being used in the best way. I hear a lot of emphasis on “Average Exit Velocity,” and I wonder if that has the potential to be misleading. I thought maybe what we need to know about a hitter is not average exit velocity but frequency of high-velocity batted balls.

In other words, it ain’t how hard the batter hits it, but how often the batter hits it hard.

The Law of Averages

The issue with averages is that they can sometimes disguise distributions of values. Here’s an example: You’re at a stats seminar, in a large room with 1,000 other guys, and you learn that the average net worth of all the guys in the room is $200,000. You are worth around $200 grand (presumably, you don’t play baseball for a living), and so are most of the other guys you know in the room. So the average is pretty accurate in describing the individual people in the room. They’re all worth around $200 thou.

Meanwhile, your buddy is at a baseball-card convention, in another large room with another 1,000 guys. The average net worth is also $200 large. Your buddy knows he's worth well less than that amount—that’s what investing in baseball cards will do—and he knows so are the other idle layabouts insightful valuators in the room with him. But over there in the corner stands Derek Jeter, taking time off from imploding the Marlins. And of course, his $185-million net worth has inflated the average of the overall room—so much that the average net worth of everyone other than Derek Jeter in that room is about $15 grand, but the overall net worth is still $200,000.

Now, Back To the Point

At this juncture, you might well be asking what all of this has to do with Exit Velocity. And frankly, I’m glad you asked, because I’m kind of losing track of that myself.

Oh, now I remember: just because a batter averages a high EV might not mean he has a lot of high-EV batted balls. His average could be inflated by a small number of very high-EV balls, which are hugely productive in fantasy terms, offsetting many poorly-hit balls, which... aren’t.

So I looked at 2017. Here’s a list of the 21 hitters (min 200 PA) who had average EVs of 91 MPH or higher:

It’s a pretty respectable list, with a lot of fine hitters. But names like Adam Lind, Kendrys Morales, and Alex Avila (!) made me wonder if we’re missing something—if there’s something going on with shape of those averages. Are these averages representative of the individual hitters? Or do some batters in the list have a Derek Jeter in the convention hall raising their average EV?

Actually, uh ... no. When I studied on it for a spell, the hypothesis that lasted about as long as Britney Spears’ marriage to whatever that guy’s name was.

Among the bottom guys on the list, it turned out that they all topped 90 MPH in EV between 55% and 60% of their batted-ball events (BBE). They knobbed out batted balls at lower than 60 MPH at about the same rates, around 3-4%.

The top of the list was much the same story, although the number of BBE over 90 was a little higher, in the low 60-percent range (with Khris Davis the outlier at 70%). Davis and Nelson Cruz also had higher sub-60 MPH BBEs, and were the only hitters with Median EV lower than their Average EV, so there might be a bit of average-inflating going on with them.

Conclusion

We’re still learning our way around these new metrics, and they should and will be explored in more detail, both here and elsewhere. For now, though, we can probably feel pretty comfortable in suggesting that hitters with high EVs are probably going to be productive hitters. On the average.